Rheumatoid Arthritis (RA) is a chronic autoimmune disease affecting synovial joints causing joint destruction, deformity that may lead to disability. There are many risk factors affecting RA including hormones as prolactin (PRL) and its proteolytic cleavage product known as vasoinhibin. This study was case control study conducted in Al-Azhar Rheumatology and Rehabilitation, clinical pathology departments for girls to assess levels of prolactin and vasoinhibin in serum of 60 rheumatoid arthritis patients versus 30 controls. Also, to assess the correlation of serum prolactin and vasoinhibin levels with laboratory and clinical parameters of rheumatoid arthritis patients. Our study revealed high positive statistically significant increase in PRL and vasoinhibin in patients than control. Prolactin showed positive significant correlation with number of tender joints and number of swollen joints, vasoinhibin, ESR, CRP, CDAI, DAS-28 with P-value<0.05. serum Vasoinhibin showed positive high statistical significance correlation with number of tender joints, number of swollen joints, patient and physician global assessments, ESR, DAS-28, CDAI with P-value <0.001, while with prolactin, VAS with P-value<0.05.